Most modern buildings use some sort of an HVAC system to control the environment conditions inside of the building. Such HVAC systems can be configured to control a number of different environmental conditions including, for example, temperature, humidity, air quality and/or other environmental conditions, as desired. In many HVAC systems, air from the building's inside space is drawn into return ducts and provided back to the HVAC system, where the return air is conditioned and provided back to the inside space. To meet desired ventilation requirements, some HVAC systems include a demand control ventilation system (DCV). DCV systems often include an exhaust port for exhausting at least some of the return air to the outside environment, and/or an intake port for bringing fresh air into the HVAC system. In some instances, a damper system is provided to control how much return air is exhausted and/or how much outside air is brought into the building. In many instances, the air supplied by the HVAC system to the inside space can be a mixture of fresh outside air and return air, depending on the conditions.
In some cases, an exhaust and/or intake port can be part of an economizer unit, which in some instances can help provide the demand control ventilation function. That is, in addition to providing a desired level of ventilation to the building, such an economizer may, under certain conditions, act as a first stage of cooling to help decrease energy usage of the HVAC system. In one example, an economizer may draw in cooler outside air to provide essentially “free” cooling during some cooling cycles.
In many cases, economizer/DCV systems (e.g. >60%) are not properly calibrated during the commissioning process, or are never commissioned at all. Calibration during the commissioning process can be considered complicated and time consuming for a typical installation technician. Even if properly calibrated during the commissioning process, the calibration may be completed under certain environmental conditions. Over time, and as the environmental conditions or the performance of the system components changes, the initial calibration may become less than optimal.